On one hand, I've done that with my expectations set rather low, after the disappointment caused by Divinity 2: DKS; another title by Larian Studios.
To make a long story short, DKS was an OK game in general, but a rather bad game about dragons - which isn't a good thing at all, given that this is supposed to be one of its main selling points.

On the other hand, I've looked up a bit of Dragon Commander gameplay footage on YouTube first, and it looked like it would be fun.
Or at least, certainly more fun than DKS was, in any case.

At the time of writing this, I've only cleared the first chapter, so I certainly won't speak for the entire game - nor regarding its overall length, which can be quite variable due to this game's nature, anyhow.
However, I do feel that I've already experienced most of its core gameplay mechanics, so let me comment on that:

To begin with, I definitely agree with AT's assessment that Divinity: DC is a game best described as "strange".
Personally, I'd also tack "and kinda silly" onto that, but more about that later.
It certainly doesn't take itself too seriously - however, at least that doesn't prevent it from being fun to play.

The core gameplay is turn-based, with each turn consisting of a "strategic phase", a "tactical phase", and (usually, but not always) also one or more "battle phase(s)", in that order.
The "strategic phase" is basically a political simulator, with a romancing element thrown in as well; I guess that's more or less a contractual obligation nowadays?
This is followed by the "tactical phase", which takes place on a map of the general area. This is where you build and move "units" (more like squads, actually) to attack or defend various territories. There are also other possible actions in this phase, such as building special buildings, or using "influence cards". After ending your turn, the enemies move their units, which can (and usually does) lead to direct conflicts.
Now, depending on the unit movements, and any conflict(s) which might have resulted, this can be followed by the "battle phase(s)", which form the "meat" of the game; as opposed to the planning phases - which would be the "bones".

For the "battle phase", first you select the commander - that can be either you, or one of the AI commanders.
If you select the AI (booooring!), this costs a variable amount of gold depending on who exactly you choose, and the game then essentially calculates the outcome of the battle based on the amounts and types of units on both sides, as well as a bunch of other factors.
Helpfully, there's a "% chance of victory" prediction visible, which is a fairly good indicator of how the AIs might fare.

However, if you choose to lead the battle yourself, then it starts what is essentially an RTS game, but with dragons thrown into the mix.
The player dragon (you) is generally rather overpowered - which would ordinarily break the game wide open. There are a few factors acting to mitigate that, though:

At the start of the battle, there's a long delay (over a minute) before you can assume dragon form. This is to prevent you from reducing the enemy base(s) to naught but dust and rubble before they have a real chance to defend themselves.

20 "recruits" (those are your "resource points") are required to take dragon form for the first time - and also every subsequent time after your health goes down to 0. Note that 20R is a rather steep price to pay during the first 2-3 minutes of battle.

Anti-air units hit hard - and they fire homing projectiles, which can be quite tricky to avoid. A few AA units on their own are quite manageable, but a whole platoon of them will grind you into mincemeat in mere seconds. There's a rapid evade/dash move available, to help avoid taking severe damage in such situations - but doing that still leaves the enemies disappointingly unroasted.

When in dragon form, you have rather limited control over your forces.

Later on, there are also enemy dragons to fight, as well. I haven't gotten there yet, though.

To put it bluntly, it's not at all feasible to solo the entire enemy army as a dragon. Instead, there's a strong co-op spirit at play here: you are there to provide support for your units, and they'll cover for you when nearby - enabling everyone on your side to survive decidedly more unshredded, as opposed to the alternative outcomes.
To that end, there's not only a basic fireball attack, but also a wide variety of researchable skills, both active and passive. These come in various flavors - many are purely offensive, but some have defensive properties, and others are "support skills" - such as healing/regeneration, various buffs for allied units, and debuffs for enemy units.
So yeah, using the dragon properly can make quite a significant difference; frequently enough to turn even an otherwise hopeless situation into a survivable one.

Do not be deceived by the "% chances of victory" indicator, though - seems like that's accurate for the commander AIs only; it appears to correlate very poorly with the actual difficulty of the RTS fights.
For example, in one of my turns I've entered a battle which was predicted as only having a 30-35% chance of winning, and looked decidedly hopeless "on paper" - yet in the end I had found little difficulty in thoroughly crushing the enemy forces, while suffering very little losses myself.
However, on the very next turn, there was a battle in a different area, where I had a decisive advantage - the "chance to win" at over 70%.
It took place on a very symmetrical 1-on-1 map, so we both had access to the same type and amount of building sites, and I had a defensive advantage due to the game's "entrenchment" mechanic. But in spite all of that, by the second minute I had already found myself at a numerical disadvantage - and it promptly turned into a brutal battle of attrition, rapidly depleting almost all of my resources, and resulting in getting pushed back all the way to my base. Ultimately, it was still a victory for me; but only by the narrowest of margins.

Which brings me straight to the next point: it's a challenging game all right - but while tough, it nonetheless feels fair; and the artificial restrictions it imposes on the player aren't nearly as egregious as they were in DKS. Clearly, the folks at Larian Studios have been paying attention, and have learned their lessons well from their earlier misadventure.Although I have failed (miserably, no less!) numerous times in my early attempts at this game, in all of the cases so far I could reliably trace the root cause to some major blunder(s) on my part - as opposed to some arbitrary, bizarre and inexplicable reason (such as a blatantly cheating enemy AI, for example).

Now, as for DC's weak points:
As I've already mentioned, this game is quite silly. Many of the NPCs in it are best described as "walking stereotypes".

Also, who had the bright idea to attach a jetpack to a dragon? Mere words cannot adequately describe just how ridiculous that is - it has to be seen to be believed.

Incredibly, this is even more baffling than the fateful decision to have ground enemies disappear after transforming into a dragon in DKS.
At least that one had an actual real-life technical reason, even though it was still a totally boneheaded move in the end.
It's like trying to attach a 3D printer extruder to a CNC milling machine (or - far worse - the other way around!) - sure, it can "kinda" work for the most part; but when taken as a whole, the result is going to be disappointing at best.

Normally I'd also go ahead and say that this whole "dragon jetpack" thing isn't even remotely plausible on both aerodynamic and engineering grounds.
But let's face it, DC didn't merely cross that line - it has jetpacked itself far clear of it, and trying to counter that with any kind of argument is about as useful as attempting to slay a fire dragon while armed only with a wooden club.

Divinity: DC is pretty much built around that whole ludicrous premise, and tries its best to provide a "logical" in-game explanation for this raving nonsense.
Unfortunately, I'm pretty sure that this puts it in a direct contradiction with the lore established in the other Divinity games - although admittedly I know rather little of that, at least beyond what had been shown in DKS.
What I am certain of though, is that DC takes place long before the events of DKS - and what we saw in DKS stands at odds with an earlier history of countless apocalyptic battles having been fought all over the realm with technologically advanced weaponry.

Also, of course everything can't possibly go too well - Divinity: DC has been causing me technical problems right off the bat.
Fire it up... immediate BSOD pointing to atikmdag.sys. Ahh, the "good old" CrossFire crash.
All right, it seems that the primary culprit was ULPS, which had been left enabled for no good reason. Also updated the Radeon drivers as well, for good measure.
Start again... no crashes this time, but the mouse cursor (not the crosshair, though) flickers like mad - obviously some issue caused by AFR. No fix in sight, however - other than by disabling CrossFire entirely.
In the end, I just put up with it, though. After a few minutes of playing, the flickering cursor stops bothering me; it's a small price to pay for having a much better framerate.

Performance... without CrossFire, it's downright abysmal on my system.With CrossFire disabled I'm only getting 25-30fps, with brief dips as low as 15fps in some cases. "Playable"? Yes, more or less - but very unimpressive, and visibly jerky. Not great in a game like this, which involves a lot of relatively rapid movement.
And that's despite my system being considerably above the "recommended" hardware requirements. (for reference: AMD 8-core 4.0GHz CPU, two R7 260x 2GB GPUs, 32GB RAM, 3 SSDs)
Strangely, there seems to be little difference in performance between the "medium" and "ultra" graphical profiles.
Even more strangely - on my system, with CrossFire disabled, the autodetection routine still selects "ultra", despite the horrid framerate which results. Perhaps it erroneously detects the (disabled) second GPU as still being active?
Of course with CrossFire enabled, the performance is certainly acceptable - at least if you can live with the resulting "disco mouse cursor" bug.

Lack of attention to detail: the dragon doesn't have a proper gliding animation, despite there having been one in DKS. Why?
Curiously, there actually is a "gliding" animation in this game - but it isn't being used in the expected way, which I find rather inexplicable.
It would seem that whoever was in charge of the dragon animations has somehow never seen any sort of a living bird in flight...

Bizarre interface design / basic usability failure: why isn't it possible to bring up the menu while controlling the dragon? Dear game developers: even if you don't want me to save, load, or change any settings while doing that, at least let me pause the bloody game, dagnabit!
Also, I find it strange why there are options available for saving/loading (as well as the quicksave/quickload key bindings) during the RTS part, but they aren't available (greyed out). Quite likely there's something about this that I don't know yet...

To summarize:

Challenging, but fair.

Doesn't feel tedious and/or too repetitive.

Throws some interesting variety into the mix.

The RTS part is geared towards hitting hard and fast, as opposed to "turtling up".

Fun, action-packed dragon gameplay.

It's kinda silly. But as to whether that's a good or a bad thing, it's up to the player to decide.

Feels a bit unpolished in some respects.

Underwhelming performance, even on hardware exceeding the recommended minimum by a healthy margin.

Appears to have poor CrossFire support.

Judgment: Fun.
Definitely a positive improvement on the dragon gameplay from DKS, and a refreshing spin on classic RTS action; just don't try to approach it too seriously.

That's a well written and comprehensive review. I won't spoil it for you by going into too much detail but you mentioned that you have only completed the first stage. It gets a whole lot more silly as it progresses but yet it maintains it's humour. There's even a hint of bestiality later on depending on how you view it which was a bit disturbing. It's a hard & challenging game it took me several attempts to complete the final stage. Saving regularly in different slots / backing up saves is recommended.

Music is great written by the late Kirill Prokovsky Russian composer who made all of the divinity game series music up until Original Sin 2 and it has a silly but fun gameplay which can become frustrating at times. I didn't fare well with the RTS sections and often opted for 'auto resolve' mode. RTS and turn based combat games are not something I normally play but Larian's games are the exception.

I didn't have any performance issues. At the time it was played on an AMD Phenom 2 3.4Ghz with 8gb RAM and R7800 series graphics card - I forget exactly which model.

By fire and by blood I join with thee in the Order of the Flame!Webmaster of Arokh's Lair

With CrossFire disabled, it was a similar experience to running Skyrim on my old computer: despite the low-ish framerate, most of the time it was reasonably smooth - but it did become very noticeably jerky when panning the camera quickly, though.
I might've made it sound a lot worse than it actually was. Then again, I had expected somewhat more out of this hardware.

One thing that irks me though, is that there's only an option to toggle antialiasing in DC, but not to select the AA level; taking it down one notch usually improves performance considerably, with only a minor impact on display quality.

I didn't fare well with the RTS sections and often opted for 'auto resolve' mode. RTS and turn based combat games are not something I normally play but Larian's games are the exception.

To be fair, I'm not a big fan of RTS games, either.
Or generally most heavily action-oriented games, for that matter. For example, I have tried DMC3 & 4 a couple years ago, but in my hands it was a total wash; and using the keyboard instead of a controller didn't help matters any, either.

The last "true RTS" game which I have played for any significant length of time was the ancient "Earth 2140" (not the sequel, Earth 2150, though!); actually, I played it to completion - at least once with each of the 2 factions.

Also I had picked up Freeciv (a turn based strategy game) a couple of times over the last decade or so, but each time I invariably dropped it because of boredom and/or tedium, not more than 100-200 turns into the game. It's OK (and even kinda fun) at first, but there's a lot of micromanagement to do, and that only gets worse as time passes and you gain more cities and units.
I guess I'm just not cut out for that kind of gameplay.

Age of Empires 2 is an interesting (and rather unusual) case - it's an RTS game, but with a built-in TAS/"turn based" feature, due to its "active pause" mode - as in, you can select and give commands to your units while the game is paused. I had countless hours of fun using (and abusing) that feature alone.

So yeah, you can probably see where I'm going with that.
As a standalone RTS without the dragon part, DC would've been average at best. But as it is, it manages to be very fun.
Basically, in terms of the dragon action, it's more or less what we have missed out on in DKS (but obviously not counting the "commanding your troops" part).
It's also notable for how it has managed to successfully integrate an inherently overpowered gameplay element (the dragon) which would ordinarily lead to ridiculous brokenness; something that Drakan has long since set a great example for.
And the "political simulator" aspect manages not to be long-winded and mind-numbingly boring, which is also nice; compare that to my earlier remark about Freeciv.

If you were to look at my statistics, I have spent (on average) over one third of each battle in dragon mode.
And it took me five turns to complete the first chapter, could've possibly been just four if I had not wasted a turn defending a formerly-neutral territory I had (perhaps unwisely) claimed in an earlier turn; although I have a feeling that maybe I had been too fast, since now I'm not sitting too pretty with my research points and techs.
I had to auto-resolve one fight, but only because there were two in a single turn, and you obviously can't fight in two different places at the same time.
For the record, so far I've been playing on "normal" difficulty - and that feels about right.